The present invention pertains to a sorption unit, to buffer means, to a condenser/evaporator unit, and to an air conditioning apparatus composed of these components.
The aim of air conditioning rooms on one hand lies in the continuous air replacement and on the other hand in creating defined temperature and climatic conditions, i.e. regulation of air temperature, moisture and/or filtering of air. Air conditioning in the sense of the present invention in first place is a change in temperature either by an “air conditioning system” for cooling, a heat pump system or another application.
In air-conditioning in terms of temperature presently, e.g. methods are used in which the sorption action is initiated by cooling down a sorption part and an working medium is evaporated in an evaporator. The working medium is exothermally sorbed, such as by adsorption, in a sorption medium and in a subsequent endothermic reaction (regeneration phase) the working medium is desorbed.
The apparatus used for realization of this method is described in DE 42 33 062 and essentially consists of several elongated sorption vessels (cooker absorber part) which over a part of their length are filled with zeolite serving as sorption medium and in this part form an adsorber. The other part of the length forms a condenser/evaporator zone (evaporator). The sorption vessels are rotating in two coaxial housings on an orbit and therein are located with the cooker absorber part in one housing and with the evaporator part in the other housing. The housing enclosing the cooker absorber parts comprises an entry and an outlet for a gaseous heat carrier medium so that the heat carrier medium on its flow path through the housing withdraws heat from the cooker absorber parts as well as supplies heat thereto.
The cooker absorber part comprises elongated flat hollow bodies bent in cross-sectional area, which are produced from high-grade steel sheets of approximately 0.1 mm thickness, the surface of these sheets is smooth. On the bottom sides, sheets bent in wave-like manner are arranged. The sheets are hold together by ambient air pressure. The sheets of about 600 mm length and 80 mm width are coated with zeolite, the zeolite layer during manufacture being applied in a multiple layer coating process. The bends touch the smooth high-grade steel sheet and thereby are supporting it. By this shape channels are formed through which the water vapor is guided.
It is in particular the costly manufacture which results from the fact that at first the sheet must be shaped and coated with zeolite, wherein such coating may be carried out in one or in several layers. A further disadvantage has to be seen in the fact that the zeolite layer has to be applied in thin layer, because zeolite is not a good thermal conductor and gas permeability of zeolite is not very good.
The major problem, however, results from the fact that the connection between the sheet and the zeolite frequently is not permanent, since the steel sheet during rotation passes hot and cold temperature zones and consequently is subject to continually changing thermal expansion (e.g. in the case when the sheets form the blades of a rotor). For this reason it may occur that during operation zeolite layers become detached—either in some areas or completely—so that the coating is destroyed, the channels are blocked or the thermal transition is carried out non-uniformly. In the places where the zeolite layer is destroyed, the function of the sheets and/or the rotor comprising the sheets is worsened.
A further aggravation of the air-conditioning apparatus results from the problems in the evaporator area. The generic evaporator—as well as the temperature insulation area between evaporator and sorption zone (called buffer means)—include the problem that it is not avoided sufficiently that during adsorption of the water in zeolite also larger water drops are entrained by the evaporator to enter the sorption unit so that water drops can enter the zeolite portion directly. This impairs efficiency of the air-conditioning system, since the water drops have not absorbed heat from the room surrounding the evaporator.